Derivative Instruments and Hedging Activities Derivative Gain (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Fair value of interest rate derivatives	$ (194)	$ 191
Interest Rate Swap No. 2 [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, term of contract	5 years
Fair value of interest rate derivatives	$ 135	70
Unrealized gain (loss) on interest rate cash flow hedges	$ (64)	165
Interest Rate Swap No. 1 [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, term of contract	10 years
Fair value of interest rate derivatives	$ (70)	(492)
Unrealized gain (loss) on interest rate cash flow hedges	133	361
Interest Rate Swap [Domain]
Derivative Instruments, Gain (Loss) [Line Items]
Fair value of interest rate derivatives	65	(422)
Unrealized gain (loss) on interest rate cash flow hedges	$ 69	$ 526